{
  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "## 12.9 Python\u7684\u5168\u5c40\u9501\u95ee\u9898\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "### \u95ee\u9898\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u4f60\u5df2\u7ecf\u542c\u8bf4\u8fc7\u5168\u5c40\u89e3\u91ca\u5668\u9501GIL\uff0c\u62c5\u5fc3\u5b83\u4f1a\u5f71\u54cd\u5230\u591a\u7ebf\u7a0b\u7a0b\u5e8f\u7684\u6267\u884c\u6027\u80fd\u3002"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "### \u89e3\u51b3\u65b9\u6848\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u5c3d\u7ba1Python\u5b8c\u5168\u652f\u6301\u591a\u7ebf\u7a0b\u7f16\u7a0b\uff0c\n\u4f46\u662f\u89e3\u91ca\u5668\u7684C\u8bed\u8a00\u5b9e\u73b0\u90e8\u5206\u5728\u5b8c\u5168\u5e76\u884c\u6267\u884c\u65f6\u5e76\u4e0d\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u3002\n\u5b9e\u9645\u4e0a\uff0c\u89e3\u91ca\u5668\u88ab\u4e00\u4e2a\u5168\u5c40\u89e3\u91ca\u5668\u9501\u4fdd\u62a4\u7740\uff0c\u5b83\u786e\u4fdd\u4efb\u4f55\u65f6\u5019\u90fd\u53ea\u6709\u4e00\u4e2aPython\u7ebf\u7a0b\u6267\u884c\u3002\nGIL\u6700\u5927\u7684\u95ee\u9898\u5c31\u662fPython\u7684\u591a\u7ebf\u7a0b\u7a0b\u5e8f\u5e76\u4e0d\u80fd\u5229\u7528\u591a\u6838CPU\u7684\u4f18\u52bf\n\uff08\u6bd4\u5982\u4e00\u4e2a\u4f7f\u7528\u4e86\u591a\u4e2a\u7ebf\u7a0b\u7684\u8ba1\u7b97\u5bc6\u96c6\u578b\u7a0b\u5e8f\u53ea\u4f1a\u5728\u4e00\u4e2a\u5355CPU\u4e0a\u9762\u8fd0\u884c\uff09\u3002"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u5728\u8ba8\u8bba\u666e\u901a\u7684GIL\u4e4b\u524d\uff0c\u6709\u4e00\u70b9\u8981\u5f3a\u8c03\u7684\u662fGIL\u53ea\u4f1a\u5f71\u54cd\u5230\u90a3\u4e9b\u4e25\u91cd\u4f9d\u8d56CPU\u7684\u7a0b\u5e8f\uff08\u6bd4\u5982\u8ba1\u7b97\u578b\u7684\uff09\u3002\n\u5982\u679c\u4f60\u7684\u7a0b\u5e8f\u5927\u90e8\u5206\u53ea\u4f1a\u6d89\u53ca\u5230I/O\uff0c\u6bd4\u5982\u7f51\u7edc\u4ea4\u4e92\uff0c\u90a3\u4e48\u4f7f\u7528\u591a\u7ebf\u7a0b\u5c31\u5f88\u5408\u9002\uff0c\n\u56e0\u4e3a\u5b83\u4eec\u5927\u90e8\u5206\u65f6\u95f4\u90fd\u5728\u7b49\u5f85\u3002\u5b9e\u9645\u4e0a\uff0c\u4f60\u5b8c\u5168\u53ef\u4ee5\u653e\u5fc3\u7684\u521b\u5efa\u51e0\u5343\u4e2aPython\u7ebf\u7a0b\uff0c\n\u73b0\u4ee3\u64cd\u4f5c\u7cfb\u7edf\u8fd0\u884c\u8fd9\u4e48\u591a\u7ebf\u7a0b\u6ca1\u6709\u4efb\u4f55\u538b\u529b\uff0c\u6ca1\u5565\u53ef\u62c5\u5fc3\u7684\u3002"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u800c\u5bf9\u4e8e\u4f9d\u8d56CPU\u7684\u7a0b\u5e8f\uff0c\u4f60\u9700\u8981\u5f04\u6e05\u695a\u6267\u884c\u7684\u8ba1\u7b97\u7684\u7279\u70b9\u3002\n\u4f8b\u5982\uff0c\u4f18\u5316\u5e95\u5c42\u7b97\u6cd5\u8981\u6bd4\u4f7f\u7528\u591a\u7ebf\u7a0b\u8fd0\u884c\u5feb\u5f97\u591a\u3002\n\u7c7b\u4f3c\u7684\uff0c\u7531\u4e8ePython\u662f\u89e3\u91ca\u6267\u884c\u7684\uff0c\u5982\u679c\u4f60\u5c06\u90a3\u4e9b\u6027\u80fd\u74f6\u9888\u4ee3\u7801\u79fb\u5230\u4e00\u4e2aC\u8bed\u8a00\u6269\u5c55\u6a21\u5757\u4e2d\uff0c\n\u901f\u5ea6\u4e5f\u4f1a\u63d0\u5347\u7684\u5f88\u5feb\u3002\u5982\u679c\u4f60\u8981\u64cd\u4f5c\u6570\u7ec4\uff0c\u90a3\u4e48\u4f7f\u7528NumPy\u8fd9\u6837\u7684\u6269\u5c55\u4f1a\u975e\u5e38\u7684\u9ad8\u6548\u3002\n\u6700\u540e\uff0c\u4f60\u8fd8\u53ef\u4ee5\u8003\u8651\u4e0b\u5176\u4ed6\u53ef\u9009\u5b9e\u73b0\u65b9\u6848\uff0c\u6bd4\u5982PyPy\uff0c\u5b83\u901a\u8fc7\u4e00\u4e2aJIT\u7f16\u8bd1\u5668\u6765\u4f18\u5316\u6267\u884c\u6548\u7387\n\uff08\u4e0d\u8fc7\u5728\u5199\u8fd9\u672c\u4e66\u7684\u65f6\u5019\u5b83\u8fd8\u4e0d\u80fd\u652f\u6301Python 3\uff09\u3002"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u8fd8\u6709\u4e00\u70b9\u8981\u6ce8\u610f\u7684\u662f\uff0c\u7ebf\u7a0b\u4e0d\u662f\u4e13\u95e8\u7528\u6765\u4f18\u5316\u6027\u80fd\u7684\u3002\n\u4e00\u4e2aCPU\u4f9d\u8d56\u578b\u7a0b\u5e8f\u53ef\u80fd\u4f1a\u4f7f\u7528\u7ebf\u7a0b\u6765\u7ba1\u7406\u4e00\u4e2a\u56fe\u5f62\u7528\u6237\u754c\u9762\u3001\u4e00\u4e2a\u7f51\u7edc\u8fde\u63a5\u6216\u5176\u4ed6\u670d\u52a1\u3002\n\u8fd9\u65f6\u5019\uff0cGIL\u4f1a\u4ea7\u751f\u4e00\u4e9b\u95ee\u9898\uff0c\u56e0\u4e3a\u5982\u679c\u4e00\u4e2a\u7ebf\u7a0b\u957f\u671f\u6301\u6709GIL\u7684\u8bdd\u4f1a\u5bfc\u81f4\u5176\u4ed6\u975eCPU\u578b\u7ebf\u7a0b\u4e00\u76f4\u7b49\u5f85\u3002\n\u4e8b\u5b9e\u4e0a\uff0c\u4e00\u4e2a\u5199\u7684\u4e0d\u597d\u7684C\u8bed\u8a00\u6269\u5c55\u4f1a\u5bfc\u81f4\u8fd9\u4e2a\u95ee\u9898\u66f4\u52a0\u4e25\u91cd\uff0c\n\u5c3d\u7ba1\u4ee3\u7801\u7684\u8ba1\u7b97\u90e8\u5206\u4f1a\u6bd4\u4e4b\u524d\u8fd0\u884c\u7684\u66f4\u5feb\u4e9b\u3002"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u8bf4\u4e86\u8fd9\u4e48\u591a\uff0c\u73b0\u5728\u60f3\u8bf4\u7684\u662f\u6211\u4eec\u6709\u4e24\u79cd\u7b56\u7565\u6765\u89e3\u51b3GIL\u7684\u7f3a\u70b9\u3002\n\u9996\u5148\uff0c\u5982\u679c\u4f60\u5b8c\u5168\u5de5\u4f5c\u4e8ePython\u73af\u5883\u4e2d\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528 multiprocessing \u6a21\u5757\u6765\u521b\u5efa\u4e00\u4e2a\u8fdb\u7a0b\u6c60\uff0c\n\u5e76\u50cf\u534f\u540c\u5904\u7406\u5668\u4e00\u6837\u7684\u4f7f\u7528\u5b83\u3002\u4f8b\u5982\uff0c\u5047\u5982\u4f60\u6709\u5982\u4e0b\u7684\u7ebf\u7a0b\u4ee3\u7801\uff1a"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {},
      "outputs": [],
      "source": [
        "# Performs a large calculation (CPU bound)\ndef some_work(args):\n    ...\n    return result\n\n# A thread that calls the above function\ndef some_thread():\n    while True:\n        ...\n        r = some_work(args)\n    ..."
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u4fee\u6539\u4ee3\u7801\uff0c\u4f7f\u7528\u8fdb\u7a0b\u6c60\uff1a"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {},
      "outputs": [],
      "source": [
        "# Processing pool (see below for initiazation)\npool = None\n\n# Performs a large calculation (CPU bound)\ndef some_work(args):\n    ...\n    return result\n\n# A thread that calls the above function\ndef some_thread():\n    while True:\n        ...\n        r = pool.apply(some_work, (args))\n        ...\n\n# Initiaze the pool\nif __name__ == '__main__':\n    import multiprocessing\n    pool = multiprocessing.Pool()"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u8fd9\u4e2a\u901a\u8fc7\u4f7f\u7528\u4e00\u4e2a\u6280\u5de7\u5229\u7528\u8fdb\u7a0b\u6c60\u89e3\u51b3\u4e86GIL\u7684\u95ee\u9898\u3002\n\u5f53\u4e00\u4e2a\u7ebf\u7a0b\u60f3\u8981\u6267\u884cCPU\u5bc6\u96c6\u578b\u5de5\u4f5c\u65f6\uff0c\u4f1a\u5c06\u4efb\u52a1\u53d1\u7ed9\u8fdb\u7a0b\u6c60\u3002\n\u7136\u540e\u8fdb\u7a0b\u6c60\u4f1a\u5728\u53e6\u5916\u4e00\u4e2a\u8fdb\u7a0b\u4e2d\u542f\u52a8\u4e00\u4e2a\u5355\u72ec\u7684Python\u89e3\u91ca\u5668\u6765\u5de5\u4f5c\u3002\n\u5f53\u7ebf\u7a0b\u7b49\u5f85\u7ed3\u679c\u7684\u65f6\u5019\u4f1a\u91ca\u653eGIL\u3002\n\u5e76\u4e14\uff0c\u7531\u4e8e\u8ba1\u7b97\u4efb\u52a1\u5728\u5355\u72ec\u89e3\u91ca\u5668\u4e2d\u6267\u884c\uff0c\u90a3\u4e48\u5c31\u4e0d\u4f1a\u53d7\u9650\u4e8eGIL\u4e86\u3002\n\u5728\u4e00\u4e2a\u591a\u6838\u7cfb\u7edf\u4e0a\u9762\uff0c\u4f60\u4f1a\u53d1\u73b0\u8fd9\u4e2a\u6280\u672f\u53ef\u4ee5\u8ba9\u4f60\u5f88\u597d\u7684\u5229\u7528\u591aCPU\u7684\u4f18\u52bf\u3002"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u53e6\u5916\u4e00\u4e2a\u89e3\u51b3GIL\u7684\u7b56\u7565\u662f\u4f7f\u7528C\u6269\u5c55\u7f16\u7a0b\u6280\u672f\u3002\n\u4e3b\u8981\u601d\u60f3\u662f\u5c06\u8ba1\u7b97\u5bc6\u96c6\u578b\u4efb\u52a1\u8f6c\u79fb\u7ed9C\uff0c\u8ddfPython\u72ec\u7acb\uff0c\u5728\u5de5\u4f5c\u7684\u65f6\u5019\u5728C\u4ee3\u7801\u4e2d\u91ca\u653eGIL\u3002\n\u8fd9\u53ef\u4ee5\u901a\u8fc7\u5728C\u4ee3\u7801\u4e2d\u63d2\u5165\u4e0b\u9762\u8fd9\u6837\u7684\u7279\u6b8a\u5b8f\u6765\u5b8c\u6210\uff1a"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {},
      "outputs": [],
      "source": [
        "#include \"Python.h\"\n...\n\nPyObject *pyfunc(PyObject *self, PyObject *args) {\n   ...\n   Py_BEGIN_ALLOW_THREADS\n   // Threaded C code\n   ...\n   Py_END_ALLOW_THREADS\n   ...\n}"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u5982\u679c\u4f60\u4f7f\u7528\u5176\u4ed6\u5de5\u5177\u8bbf\u95eeC\u8bed\u8a00\uff0c\u6bd4\u5982\u5bf9\u4e8eCython\u7684ctypes\u5e93\uff0c\u4f60\u4e0d\u9700\u8981\u505a\u4efb\u4f55\u4e8b\u3002\n\u4f8b\u5982\uff0cctypes\u5728\u8c03\u7528C\u65f6\u4f1a\u81ea\u52a8\u91ca\u653eGIL\u3002"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "### \u8ba8\u8bba\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u8bb8\u591a\u7a0b\u5e8f\u5458\u5728\u9762\u5bf9\u7ebf\u7a0b\u6027\u80fd\u95ee\u9898\u7684\u65f6\u5019\uff0c\u9a6c\u4e0a\u5c31\u4f1a\u602a\u7f6aGIL\uff0c\u4ec0\u4e48\u90fd\u662f\u5b83\u7684\u95ee\u9898\u3002\n\u5176\u5b9e\u8fd9\u6837\u5b50\u592a\u4e0d\u539a\u9053\u4e5f\u592a\u5929\u771f\u4e86\u70b9\u3002\n\u4f5c\u4e3a\u4e00\u4e2a\u771f\u5b9e\u7684\u4f8b\u5b50\uff0c\u5728\u591a\u7ebf\u7a0b\u7684\u7f51\u7edc\u7f16\u7a0b\u4e2d\u795e\u79d8\u7684 stalls\n\u53ef\u80fd\u662f\u56e0\u4e3a\u5176\u4ed6\u539f\u56e0\u6bd4\u5982\u4e00\u4e2aDNS\u67e5\u627e\u5ef6\u65f6\uff0c\u800c\u8ddfGIL\u6beb\u65e0\u5173\u7cfb\u3002\n\u6700\u540e\u4f60\u771f\u7684\u9700\u8981\u5148\u53bb\u641e\u61c2\u4f60\u7684\u4ee3\u7801\u662f\u5426\u771f\u7684\u88abGIL\u5f71\u54cd\u5230\u3002\n\u540c\u65f6\u8fd8\u8981\u660e\u767dGIL\u5927\u90e8\u5206\u90fd\u5e94\u8be5\u53ea\u5173\u6ce8CPU\u7684\u5904\u7406\u800c\u4e0d\u662fI/O."
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u5982\u679c\u4f60\u51c6\u5907\u4f7f\u7528\u4e00\u4e2a\u5904\u7406\u5668\u6c60\uff0c\u6ce8\u610f\u7684\u662f\u8fd9\u6837\u505a\u6d89\u53ca\u5230\u6570\u636e\u5e8f\u5217\u5316\u548c\u5728\u4e0d\u540cPython\u89e3\u91ca\u5668\u901a\u4fe1\u3002\n\u88ab\u6267\u884c\u7684\u64cd\u4f5c\u9700\u8981\u653e\u5728\u4e00\u4e2a\u901a\u8fc7def\u8bed\u53e5\u5b9a\u4e49\u7684Python\u51fd\u6570\u4e2d\uff0c\u4e0d\u80fd\u662flambda\u3001\u95ed\u5305\u53ef\u8c03\u7528\u5b9e\u4f8b\u7b49\uff0c\n\u5e76\u4e14\u51fd\u6570\u53c2\u6570\u548c\u8fd4\u56de\u503c\u5fc5\u987b\u8981\u517c\u5bb9pickle\u3002\n\u540c\u6837\uff0c\u8981\u6267\u884c\u7684\u4efb\u52a1\u91cf\u5fc5\u987b\u8db3\u591f\u5927\u4ee5\u5f25\u8865\u989d\u5916\u7684\u901a\u4fe1\u5f00\u9500\u3002"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\u53e6\u5916\u4e00\u4e2a\u96be\u70b9\u662f\u5f53\u6df7\u5408\u4f7f\u7528\u7ebf\u7a0b\u548c\u8fdb\u7a0b\u6c60\u7684\u65f6\u5019\u4f1a\u8ba9\u4f60\u5f88\u5934\u75bc\u3002\n\u5982\u679c\u4f60\u8981\u540c\u65f6\u4f7f\u7528\u4e24\u8005\uff0c\u6700\u597d\u5728\u7a0b\u5e8f\u542f\u52a8\u65f6\uff0c\u521b\u5efa\u4efb\u4f55\u7ebf\u7a0b\u4e4b\u524d\u5148\u521b\u5efa\u4e00\u4e2a\u5355\u4f8b\u7684\u8fdb\u7a0b\u6c60\u3002\n\u7136\u540e\u7ebf\u7a0b\u4f7f\u7528\u540c\u6837\u7684\u8fdb\u7a0b\u6c60\u6765\u8fdb\u884c\u5b83\u4eec\u7684\u8ba1\u7b97\u5bc6\u96c6\u578b\u5de5\u4f5c\u3002"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
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